The present invention relates in general to music systems and in particular to a melody analyzer which automatically analyzes a given melody with respect to musical functions or characters of individual notes contained in the melody.
Melody analyzers of this kind are disclosed in U.S. patent applications Ser. No. 07/177,592, filed Apr. 4, 1988, and Ser. No. 07/288,001, filed Dec. 20, 1988, both assigned to the same assignee as the present application, and incorporated herein as reference. Each analyzer of these patent applications is arranged to receive chord data as well as melody data to be analyzed. A harmonic/nonharmonic tone separator is provided which compares respective notes in the melody with members of the chord (chord notes) to separate (classify) the melody notes into two groups, i.e., a harmonic (chordal) melody note and a nonharmonic melody note. The system further comprises a melody motion evaluator that evaluates motions in the melody such as pitch intervals between successive melody notes and a subclassifying device that receives from the harmonic/nonharmonic tone separator melody notes labeled with a nonharmonic melody note to subclassify these melody notes based on classified harmonic/nonharmonic results of those melody notes around the respective nonharmonic labeled melody notes and based on evaluated motions associated with the respective nonharmonic labeled melody notes and their surrounding melody notes in order to further identify musical functions of the nonharmonic labeled melody notes.
The melody analyzer described above is based on the premise that any harmonic melody note (melody note that corresponds to one of the chord members) can freely be used in a melody, but a nonharmonic melody note (a note outside of the chord pitch contents) can only be used in restricted musical conditions of melody context. The above melody analyzer has no choice but to differentiate harmonic melody tones from nonharmonic melody tones unless additional reference information other than the chord is provided for comparison with the melody.
As experienced, there are a variety of melodies in music. Some melodies consist of only harmonic tones in which every melody note is a member of a coexisting chord in a succession of chords. Some melodies consist of harmonic tones freely used therein and restrictively used nonharmonic tones. In still some other melodies, one or more nonharmonic (out-of-chord) tones are freely used similarly to harmonic tones while other nonharmonic tones are limitedly used only as the melody context permits. In general, notes used in a melody depend on backgrounds of the melody such as musical style. In addition, notes available in a melody, to which a chord is applied, depend on what function that melody performs in the framework of the entire music piece so that they vary with the musical structures of the piece such as tonality structure. For this reason, only a portion of the melody notes can be derived from the chord.
In the presence of such diversity of melodies, the melody analyzer discussed above has an analysis limitation because of its assumption that only harmonic tones are freely used in a melody while nonharmonic tones are avoided or only limitedly used.